Much like OSHA’s Letter of Interpretation, EPA has a series of “Frequently Asked Questions (FAQ)” in regards to their Risk Management Plan rule. Recently EPA answered a question regarding their take on “co-location” in which a tank with 1,000,000 pounds of toluene diisocyanate (TDI), which is covered under the RMP rule, but not under OSHA PSM. Considered by itself, the TDI would be Program 2 for EPA. The tank, however, is close to equipment that has chlorine above the applicable threshold and is subject to OSHA PSM and Program 3. Should the TDI tank be considered part of the same process as the equipment containing the chlorine? How does this affect the program level? EPA’s Response is…